European Journal of Wood and Wood Products最新文献

Wood modification by impregnating different types of nanomaterial-fortified polymeric resins from plant sources has emerged as a promising technique to enhance its various properties and improve performance against biodeteriorating agents. This study explores the enhancement of physico-mechanical properties and durability of Populus deltoides (poplar) wood by incorporating nano-silica (NS) into furfuryl alcohol (FA) during the furfurylation process. Three different concentrations (1%, 3%, and 5%) of NS dispersed in FA were impregnated in poplar wood using vacuum-pressure technique. Different properties such as water absorption (WA), anti-swelling efficiency (ASE), surface hardness, decay resistance against fungi and thermal stability of modified wood were evaluated. Morphological analysis using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) mapping was performed to study the distribution of NS within the wood structures. Chemical interactions amongst different components of modified wood were confirmed by Fourier-transform infrared (FTIR) spectroscopy. Results of the present study demonstrate that NS fortified furfurylated wood exhibited reduced WA (96%), improved ASE (72–79%), enhanced decay resistance (4–6% mass loss) and increased surface hardness (4% in the side grain and 40% in the end grain). Also, the improvements were observed in the thermal stability of wood by adding NS with FA. Analysis of data showed that 3% concentration of NS provided optimal results to improve properties of poplar wood. The use of renewable FA derived as by-products from agricultural resources, coupled with usage of low-concentration of nanomaterial, makes this approach environmentally sustainable, offering a green alternative to conventional treatments.

The presented research concerned the use of propolis extract as a modifier of urea-formaldehyde (UF) adhesive for the production of particleboard. The adhesive formulations differed in both the modifier content (1, 3 and 5%) and the extract concentration (50 and 70%). The results of differential scanning calorimetry, rheometric analysis of the cross-linking process and thermogravimetric analysis showed an acceleration of the curing process, a slight increase in viscosity and a decrease in the thermal stability of the cured adhesive mixtures. Moreover, the Fourier transform infrared spectroscopy analysis of the cured adhesives showed a reduction in the intensity of the peaks characteristic of the UF adhesive due to the applied modification. Furthermore, particleboards bonded with the mixtures containing 3 and 5% of 70% extract and 5% of 50% extract were characterized by significantly improved strength properties (bending strength, modulus of elasticity, internal bond), better water resistance (thickness swelling, water absorption) and reduced formaldehyde content. The adhesive mixture modified with 5% of 70% propolis extract was considered the optimal variant providing the most significant improvement in the properties of produced particleboards.

Precise modeling of the bond properties between timber and fiber-reinforced polymer (FRP) at varying temperatures is crucial for structural integrity. This study uses boosting algorithms—XGBoost, LightGBM, and CatBoost—to model the impact of thermal cycles on the bond behavior of FRP-timber using single-lap shear tests. A comprehensive dataset of 150 experimental results was compiled and processed to train and test the models. Key parameters were density, stiffness, temperatures, thermal cycling, energy absorption, ultrasonic pulse velocity (UPV) measurements, and fiber types (glass, carbon, and aramid). Genetic algorithms (GA) and a 5-fold cross-validation (CV) technique were employed to fine-tune the hyperparameters of the boosting algorithms. The results demonstrated the superior accuracy of the CatBoost model in predicting the bond characteristics. This comprehensive evaluation highlights the critical factors influencing FRP-timber composite mechanical behavior. Feature contribution analysis revealed that temperature and thermal cycles exert the most significant impact on the bond properties. The types of fibers (glass, carbon, and aramid) showed relatively low importance. This study shows that FRP-timber interface properties inform accurate predictive models and design guidelines for varying thermal cycles.

The possibility of welding wood dowels into low-density plywood substrates without a pilot hole was investigated. Sharpened beech wood dowels with a diameter of 10 mm were inserted into plywood plates made from poplar and paulownia wood at a rotational rate of 1500 rpm with a manually operated drill press. This process resulted in welded joints of considerable strength. When poplar was used, withdrawal strengths as high as those of adhesive bonds were achieved.

Based on the dowel laminate timber production method and the laminated veneer lumber (LVL) material characteristic, a new type of mass timber, known as dowel laminated veneer lumber (DLVL), was developed using small-thickness LVL made from fast-growing larch (Larix gmelinii Rupr), which could be made into beams with large cross-sections. Four-point bending tests were carried out on DLVL beams. The flexural performance of vertical DLVL (V-DLVL) and horizontal DLVL (H-DLVL) beams was compared. The impacts of lamina thickness and width on the flexural strength and effective flexural stiffness of H-DLVL beams were further investigated. The prediction formulas of the flexural capacity and effective flexural stiffness of H-DLVL beams were proposed. The results showed that the flexural strength and effective flexural stiffness of H-DLVL beams were about 2 and 8 times that of V-DLVL beams with the same cross-section, respectively. The flexural performance of H-DLVL beams made from fast-growing wood was comparable with that of other engineered wood beams. The lamina thickness combination affected the flexural performance of H-DLVL beams. When the beam cross-section was constant, the flexural strength of H-DLVL beams composed of 20 mm and 40 mm mixed thickness LVL laminae was a little higher than that of H-DLVL beams only composed of 20 mm or 40 mm thickness LVL laminae. The prediction formulas considering the size effect could successfully predict the flexural capacity, maximum deflection, and effective flexural stiffness of H-DLVL beams.

Density is one of the major decision-making criteria of medium-density fiberboard (MDF) in terms of product quality. It is therefore very important to keep this key quality characteristic of the MDF in control. This research presents an industrial implementation of Shewhart’(:stackrel{-}{text{x}}-text{s}) control charts, which are generally constructed to catch large shifts, and exponentially weighted moving average (EWMA) control chart, which is mostly used to uncover small and moderately shifts, to monitor the density in the MDF manufacture in a forest products enterprise. Besides, a process capability analysis (PCA) was used to evaluate whether or not the measured outputs of density fall inside the specification limits. As a result; it was detected that the process was not in control for both (:stackrel{-}{text{x}}-text{s}) and EWMA, which demonstrate the changes in the density. The PCA also revealed that the process did not have sufficient capability in meeting the specifications of the density. Ultimately, such studies will allow both engineers and quality control officers to monitor a large number of measurements of quality characteristics in manufacturing processes. This can make a major contribution to detecting whether quality-related issues exist in processes and thus guide practitioners in improving or maintaining the quality level. Furthermore, in light of the current study, the efforts to be carried out to identify and eliminate factors that cause the process to deviate from specifications as well as factors that cause signal generation are expected to contribute to both reducing the amount of non-conforming products and achieving a more stable process.

Wood is a typical anisotropic material with considerably lower transverse compressive strength than longitudinal compressive strength. In the field of wooden structure design and construction, the occurrence of tilting or even collapse due to transverse compression is a common challenge requiring careful consideration. Presently, reinforcement materials primarily include steel bars or screws, yet a comprehensive examination of internal force dynamics within reinforced wood is lacking. This study utilizes Japanese larch (Larix kaempferi (Lamb.) Carriere) as the wood material, reinforces the wood through the insertion of wood dowels made of Schima superba (Schima superba Gardner & Champ.), and investigates the effects of the number and length of wood dowels on the transverse compressive strength and modulus of elasticity of the wood. A simulation model is established using the finite element software to analyze stress and strain variations in samples following wood dowel implantation. The study investigates the predictive and simulated influence of wood dowel diameter on the transverse compressive strength and modulus of elasticity of wood. The main conclusions are as follows: (1) Employing a 90 mm wood dowel can effectively increase the radial and tangential compressive strength as well as the modulus of elasticity of the wood. (2) Introducing wood dowels can influence the stress and strain distribution within the internal structure of wood, with increasing trends observed as the length of the dowel increases. (3) When the length of the wood dowel amounts to 90 mm, augmenting the diameter of the wood dowel can efficaciously enhance the transverse compression strength and modulus of elasticity of the wood.

Wood is susceptible to various degradation mechanisms when exposed to dynamic environmental conditions, including hydrolysis caused by the infiltration of water into the wood cell structure. This study aims to examine the differences between the effects of two types of accelerated aging on the long-term performance of white spruce wood samples to have a better understanding of the performance of spruce wood in real-world applications. Two separate sets of samples were employed in this experimental study. One set was placed in a hydrolytic aging chamber at 90 °C and 80% relative humidity while the other set was placed in a freeze-thaw cycling chamber with temperature variations from 25 °C to -18 °C at a rate of 6 cycles per day. The aged samples were tested at regular intervals, with a testing span of 3 months for the hydrolytically aged samples and 300 cycles for the freeze-thaw aged samples. The results obtained from characterization tests showed that both aging conditions caused a significant increase in the crystallinity index of the samples. This finding highlights the potential value of subjecting wood to these conditions as a pre-treatment to standardize crystallinity levels for experimental purposes. Ultimately, the hydrolytic aging conditions were found to be more detrimental to the spruce wood samples. The samples that underwent hydrolytic aging demonstrated higher water uptake levels, lower viscoelastic properties, and lower thermal degradation temperatures than the samples that were subjected to freeze-thaw cycling.

With increased focus on sustainable building materials and the growing popularity of uncoated wooden cladding, understanding consumer acceptance of aesthetic changes becomes crucial for sustainable architectural choices. This study investigated consumer acceptance of uncoated wooden cladding in Norway, Sweden, and Germany, focusing on personality traits and perceptions. Using an online survey with 3112 participants, the study found that preference for uncoated wooden cladding was similar (around 20%) across the three countries, despite differences in the prevalence of wooden cladding. A natural consequence of weathering of wood exposed outdoors is greying of the surface. The survey presented participants with images of uncoated wooden cladding with varying degrees of grey discolouration. Participants rated the acceptability of these claddings based on their preferences. Acceptance of this discolouration differed by country, Norwegians preferred intermediate-coloured panels, Swedes preferred darker panels, and Germans accepted all panels. Personality traits measured using the Big Five personality inventory and socioeconomic factors influenced preferences. In Norway and Sweden, those accepting the discolouration of uncoated wooden cladding included introverts, highly conscientious individuals, young people, females, and those with tertiary education. Additionally, in Norway and Germany, openness to experience was linked to acceptance, while strong emotional control was significant only in Norway. This study underscores the complexity of consumer preferences for uncoated wooden cladding, demonstrating that personality traits, in conjunction with cultural and demographic variables, jointly influence perception. The findings offer valuable insights for architects, builders, and policymakers seeking to advance sustainable construction practices while optimising consumer satisfaction in the housing sector.

In order to study the compressive behavior of wood winding circular tubes at different winding angles (from 0 degrees to 90 degrees, with intervals of every 15 degrees), 28 specimens were designed for experimental research. The failure modes of the specimens were found to be dependent on the winding angle: specimens labeled WD0 and WD15 exhibited brittle fracture, specimens labeled WD45 to WD90 showed progressive crushing, and the remaining specimens experienced mixed failure. The results indicated that the compressive strength gradually decreased with the increase of winding angle. Additionally, specific energy absorption (SEA), mean crushing force (MCF) and crush force efficiency (CFE) increased with the winding angle, while peak crushing force (PCF) initially decreased and then increased. Further, an empirical equation based on a sine and cubic function was proposed to predict the compressive strength of wood winding circular tubes at different winding angles. Theoretical formulas were also introduced to predict the mean crushing force.